Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual torneio teve uma quartas de final em 2011?
 ###Tabelas: CREATE TABLE administrative_divisions_regions_and_states (administrative_divisions_regions_and_states_id AUTO_INCREMENT PRIMARY KEY, No. INT, State/Region VARCHAR, Districts INT, Town ships INT, Cities/ Towns INT, Wards INT, Village groups INT, Villages INT) CREATE TABLE public_companies (public_companies_id AUTO_INCREMENT PRIMARY KEY, State Rank by Revenue INT, Company Name VARCHAR, National Rank INT, Revenue ($billions) 2012 estimate VARCHAR, Headquarters City VARCHAR, Known for VARCHAR) CREATE TABLE mixed_doubles_performance_timeline (mixed_doubles_performance_timeline_id AUTO_INCREMENT PRIMARY KEY, Tournament VARCHAR, 2007 VARCHAR, 2008 VARCHAR, 2009 VARCHAR, 2010 VARCHAR, 2011 VARCHAR, 2012 VARCHAR, 2013 VARCHAR) CREATE TABLE honour_roll (honour_roll_id AUTO_INCREMENT PRIMARY KEY, Year INT, W: L: D VARCHAR, Position VARCHAR, Chairman VARCHAR, CEO VARCHAR, Coach VARCHAR, Captain VARCHAR, Vice-Captain VARCHAR, Best and Fairest VARCHAR, Leading Goalkicker VARCHAR) CREATE TABLE final_standings (final_standings_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Visitor VARCHAR, Score VARCHAR, Home VARCHAR, Record VARCHAR, Points INT)  
SELECT Tournament FROM mixed_doubles_performance_timeline WHERE 2011 = qf